The present invention relates generally to heating, ventilating, and air conditioning (HVAC) systems and more specifically to a state-based control system for an air handling unit (AHU) in a building HVAC system.
HVAC systems are used to monitor and control temperature, humidity, air flow, air quality, and other conditions in a building or building system. HVAC systems often include an AHU which functions intake outside air and/or return air from inside the building and to provide a supply airstream to the building at setpoint conditions. Some AHUs use a constant volume fan to provide a constant airflow directly to one or more building zones. Other AHUs use a variable volume fan and/or provide airflow to downstream variable air volume (VAV) boxes which control airflow into the building zone.
Typically, AHUs are designed to serve a heating or cooling load within a predetermined load range and must sacrifice energy efficiency to provide heating or cooling outside the predetermined range. Many AHUs also rely on downstream pressure sensors (e.g., static pressure sensors, velocity pressure sensors, etc.) or input from other control loops to achieve setpoint conditions. It would be desirable to provide an AHU that is adaptable to multiple different load conditions without sacrificing efficiency.